EP0242942B1 - Optisches Aufzeichnungsmedium und Verfahren zu dessen Herstellung - Google Patents

Optisches Aufzeichnungsmedium und Verfahren zu dessen Herstellung Download PDF

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Publication number
EP0242942B1
EP0242942B1 EP87301046A EP87301046A EP0242942B1 EP 0242942 B1 EP0242942 B1 EP 0242942B1 EP 87301046 A EP87301046 A EP 87301046A EP 87301046 A EP87301046 A EP 87301046A EP 0242942 B1 EP0242942 B1 EP 0242942B1
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Prior art keywords
layer
atomic
underlayer
recording medium
substrate
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French (fr)
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EP0242942A3 (en
EP0242942A2 (de
Inventor
Toshihiko Yoshitomi
Yoshimitsu Kobayashi
Yoshiyuki Kisaka
Hidemi Yoshida
Michikazu Horie
Takanori Mitsubischi Kasey K.K.K Tamura
Mitsuaki Mitsubischi Kasey K.k.K Ohgaki
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Mitsubishi Chemical Corp
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Mitsubishi Kasei Corp
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Priority claimed from JP61095264A external-priority patent/JPS62252543A/ja
Priority claimed from JP61142167A external-priority patent/JPS62298944A/ja
Priority claimed from JP61220833A external-priority patent/JPS6374139A/ja
Priority claimed from JP61302607A external-priority patent/JPS63155443A/ja
Priority claimed from JP61306073A external-priority patent/JPS63160027A/ja
Priority claimed from JP61307120A external-priority patent/JPS63160031A/ja
Priority claimed from JP62002966A external-priority patent/JPS63171446A/ja
Priority claimed from JP62013650A external-priority patent/JPS63182188A/ja
Application filed by Mitsubishi Kasei Corp filed Critical Mitsubishi Kasei Corp
Publication of EP0242942A2 publication Critical patent/EP0242942A2/de
Publication of EP0242942A3 publication Critical patent/EP0242942A3/en
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G11B7/2433—Metals or elements of Groups 13, 14, 15 or 16 of the Periodic Table, e.g. B, Si, Ge, As, Sb, Bi, Se or Te
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/257—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
    • G11B7/2572—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of organic materials
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G11B2007/24302—Metals or metalloids
    • G11B2007/24316—Metals or metalloids group 16 elements (i.e. chalcogenides, Se, Te)
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G11B2007/24318—Non-metallic elements
    • G11B2007/24326—Halides (F, CI, Br...)

Definitions

  • the present invention relates to an optical recording medium and to a process for producing the same.
  • the present invention relates to an optical recording medium on which information can be recorded by irradiating a laser beam on a recording layer to cause local heating to form an ablative hole or a depression in the heated part, thereby recording information, and to a reliable process for producing the optical recording medium.
  • Te films As an optical recording medium on which information can be recorded by irradiating a laser beam on a thin recording layer formed on a substrate, thereby forming a hole, a depression or a protuberance thereon, it has been hitherto known to use thin Te films. Since Te has a large light absorption coefficient, melts at a low temperature and has low thermal conductivity, it has a high recording sensitivity in the above-mentioned method. However, there is a problem that Te films tend to oxidize rapidly in air; the degradation of the light absorption efficiency caused by oxidation results in the degradation of recording sensitivity.
  • Te films The degradation resistance of Te films has been improved by using an alloy containing Se instead of Te, using lower oxides of Te or using an organic polymer layer in which Te is dispersed [for instance refer to JP-A-53-3ll04(l978), JP-A-58-54338(l983) and JP-A-57-98394(l982)].
  • the above-mentioned recording medium can be produced by a vacuum evaporation method or an ion-plating method, a sputtering method is preferably adopted because of the favorable controlability of the deposition of the films.
  • the recording layer has a non-crystalline or microcrystalline structure and the temperature at which the above-mentioned micro-structures are transformed into the polycrystalline structure of larger grain size, that is the crystallization temperature, is increased, thereby stabilizing the micro-structure of the layer at room temperature.
  • a thin recording layer of a Te based alloy containing Ge, Pb or Sn may be used [refer to JP-A-59-35356(l984)].
  • the material of the recording layer which is melted locally by the laser heating is removed from the substrate while overcoming the adhesion of the film to the substrate.
  • an underlayer comprising a thin layer of a fluorocarbon polymer has been provided between the recording layer and the substrate [JP-A-59-90246(l984)].
  • the factors contributing to the adhesion of the films to the substrate include the surface tension of the recording layer and the substrates, the molecular weight and the degree of crosslinking in the surface layer of the substrate.
  • the pit can be formed in a shorter pulse width with less laser beam power. This improves the recording sensitivity, and therefore high-speed recording and the use of a cheap semiconductor laser diode of low output power have become possible.
  • the storage capacity of the optical recording medium is large, namely that high density recording is possible.
  • the minimum size of the pit must be as small as possible. In the case where, due to the large heat conductivity of the recording layer, the region to be melted and removed by irradiation of the laser beam becomes too large and in the case where, due to the low adhesion of the recording layer to the underlayer, the amount of the substance to be removed becomes too large, the size of the pit is enlarged. In such a case high density storage is impossible.
  • the energy density of the laser beam focused on a unit area of the surface of the optical recording medium is small.
  • the laser beam output necessary to form a pit is larger. Therefore the requirement for improvement of the sensitivity of the optical recording medium is more severe in the outer region than in the inner region of the disk.
  • the combination of the material of the recording layer and the material of the substrate or the underlayer becomes an extremely important factor. Namely, in order to shorten the minimum length of the pit, it is desirable that the adhesion is larger. On the other hand, in order to improve the sensitivity, it is desirable that the adhesion is smaller. In other words, two mutually contradictary requirements must be satisfied.
  • an organic compound may be used which decomposes and/or sublimes at a low temperature while still having a high adhesion (e.g.
  • the above-mentioned sublimative pigments cannot be formed into a thin layer by sputtering or plasma polymerization. Accordingly it is not possible to use a consistent dry process to form the recording layer with sputtering.
  • Philips Technical Review, 41, No 11/12, 1983/4, pp 313-324 discloses an optical recording medium comprising a recording layer which may, for example, comprise a tellurium alloy which contains selenium.
  • the present invention provides an optical recording medium on which information can be recorded by irradiation with a laser beam, which medium comprises
  • the present invention also provides a process for producing an optical recording medium, which process comprises carrying out reactive sputtering in a gaseous mixture of a selenium fluoride gas and argon gas while using a target of Te or an alloy containing Te and Se as a target material so as to form a recording layer containing, based on the composition of the layer, from 35 to 94.9 atomic% of Te, from 5 to 25 atomic% of Se and from 0.l to 40 atomic% of F on a substrate.
  • the optical recording medium of the present invention has excellent recording performance such as high recording sensitivity, good shape of the pits, smoothness of the surface of the recording layer, uniformity of the microstructure of the recording layer, good archival stability, and low readout noise since the recording layer is non-crystalline or has a microcrystalline structure and since, preferably, an underlayer comprising a fluorocarbon polymer is disposed between the recording layer and the substrate.
  • the process of the present invention produces an optical recording medium with good reproducibility.
  • Fig. l shows a longitudinal cross sectional view of an example of an optical recording media according to the present invention
  • Fig. 2 shows an apparatus for producing the optical recording medium according to the present invention
  • Fig. 3 shows how the transmission of the recording medium obtained in Example 4 depends on the temperature
  • Fig. 4 shows the dependency of the C/N ratio of the recording medium obtained in Example ll on the recording laser power
  • Fig. 5 shows the dependency of the C/N ratio of the recording medium obtained in Example l2 on the recording laser power.
  • the substrate of the recording medium may be, for example, a plastic material such as an acrylic resin or polycarbonate resin, a metal such as aluminium or glass, or a material made by applying a thermosetting resin or photosetting resin on an above-mentioned substrate.
  • a plastic substrate has the advantages of being cheap and easy to process and has excellent optical properties.
  • the change in birefringence of the substrate over time is unfavorable.
  • the birefringence of the substrate becomes the main factor in the fluctuation of the readout light intensity.
  • a cheap plastic substrate may be used since the birefringence change thereof is small. This substrate is stabilized by annealing a recording medium of high quality, and high cost-performance can be offered.
  • the recording layer is deposited onto the substrate by reactive sputtering.
  • a glow discharge is provided in a vacuum chamber into which a gaseous mixture comprising argon gas and a selenium fluoride gas has been introduced, using the target material comprising Te or Te and Se.
  • the thickness of the deposited recording layer is, for example, from 15 to 100 nm (l50 to l000 ⁇ ), preferably from 20 to 100 nm (200 to l000 ⁇ .
  • the thickness is less than 15 nm (l50 ⁇ )
  • a completely satisfactory readout signal cannot be obtained since the reflection from the recording layer is low.
  • the thickness is more than 100 nm (l000 ⁇ )
  • the recording sensitivity of the optical recording medium is poor.
  • Te which is a component of the recording layer, is, in the process of the present invention, derived from the target material, and F, which is also a component thereof, is derived from the fluoride gas.
  • Se which is again also a component thereof, is derived from the target material containing Te and Se or the selenium fluoride gas.
  • the temperature of the substrate is necessary to maintain the temperature of the substrate at a temperature of from room temperature to a temperature sufficiently less than the softening point of the substrate during deposition, for instance at a temperature of from 40 to 50°C in the case of a polycarbonate substrate. This temperature is easily achieved even without cooling the substrate by conventional magnetron-sputtering.
  • Te alone, an alloy comprising Te and Se, and an alloy comprising Te and Se as the main component, for example further containing Pb, Sb, Sn, In or Ge, may be exemplified.
  • pre-sputtering by an inert gas is generally carried out.
  • the electric discharge conditions at the time of the pre-sputtering and the duration thereof depend on the oxidized state of the surface of the target, it is necessary to carry out the pre-sputtering carefully.
  • the fluctuation of the sputtering rate owing to the oxidation of the surface of the target can be prevented. This prevents fluctuation of the composition of the deposited film.
  • the alloy target containing Te and Se is easily prepared by an ordinary sintering method or melting method.
  • the deposition of the recording layer is carried out in a conventional radio frequency or direct current discharge sputtering apparatus using the above-mentioned target.
  • the effect of incorporating Se in the Te recording medium is to prevent degradation of the recording medium itself by oxidation.
  • the content of Se in the target is preferably from 5 to 30 atomic%.
  • the surface tension of the recording medium at the time of melting is reduced by the presence of Se, it is not favorable to make the target contain over 30 atomic% Se when the pits are to be formed by local irradiation by a laser beam and using the surface tension of the film material.
  • the amount of Se in the target is preferably from l to 5 atomic%. Even with this Se content oxidation of the surface of the target is prevented.
  • the objective element can, for example, be added into the target of Te alone or the alloy target containing Te and Se.
  • the properties of the recording medium can be controlled.
  • Se2F2, SeF4 and SeF6 are examples of the selenium fluoride gas. SeF6 is generally used. The amount of the selenium fluoride gas in the gaseous mixture is generally from 0.l to 50% by volume.
  • the amount of such a component is preferably from l to 20 atomic%.
  • the Se is contained in the layer in an amount of less than 5 atomic%, the oxidation resistance of the layer and the stability over time are poor. If the content of Se is more than 25 atomic%, the energy which is necessary for forming the holes is greater, i.e. the recording sensitivity is poor.
  • the films do not have a non-crystalline structure. If the F content is more than 40 atomic%, the substrate is apt to be damaged, and moreover the recording sensitivity is poor.
  • the recording layer film has a uniform non-crystalline structure. This is in contrast to the polycrystalline structure of a deposited layer prepared by a simple vacuum evaporation method or a sputtering method using only argon gas.
  • the reason why the deposited film has a non-crystalline structure is not clear. It could be because the molecules of the reactive gas contain fluorine atom(s), fluoride ions and fluorine radicals so that Se and Te fluorides are formed in the glow discharge plasma. These fluorides could impinge onto the substrate together with the Te and Se atoms causing etching of the glowing surface of the films, resulting in the prevention of growth of large grains.
  • the etching of the surface of the substrate slightly by the fluoride ions or fluorine radicals also uniformalizes the adhesion between the substrate and the deposited film.
  • the deposited layer contains Se as well as Te
  • oxidation-resistance which cannot be obtained by Te alone, can be obtained.
  • the reflectivity of the above-mentioned recording medium does not change at all even after being exposed, in an accelerated test, for 30 days at a temperature of 70°C and at a relative humidity of 85%.
  • the micro-structure of the film is changed. As a result it is possible to increase the stability of the crystals, the recording sensitivity and the pit form over time.
  • the recording medium before annealing has a uniform non-crystalline structure. Even after the annealing it has a stable polycrystalline structure having grains of less than 100 nm (l000 ⁇ ) diameter. It is possible to make the grain size to not above several tens nm (several hundred ⁇ ).
  • the recording medium with this grain size does not have disadvantages such as an occurrence of noise in the readout signal and a disorder of the shape of the pits.
  • non-crystalline structure as mentioned above also refers to a micro-structure having an X-ray diffraction pattern in which no clear crystal line peak can be observed, and also refers to a structure in which so-called micro-crystalline grains having a diameter of several nm (several tens ⁇ ) are present.
  • a polycrystalline structure having a grain size of less than 100 nm (l000 ⁇ ) means all micro-structures in which the largest grain size is less than 100 nm (l000 ⁇ ), and therefore includes the non-crystalline structure, the microcrystalline structure, the polycrystalline structure and a hetero-structure (a mixture of the above-mentioned three structures). Such a structure can be confirmed accurately by observing the transmission image, the diffraction pattern or the lattice image of the deposited films with transmission electron-microscopy.
  • the annealing may be carried out in a vacuum, in dried air or in a nitrogen atmosphere. However, in order to maintain the atmosphere in a uniform state, dried air or a nitrogen atmosphere is preferred.
  • the annealing is carried out in the atmosphere at a temperature of from 60°C to less than l30°C, preferably from 60°C to l00°C and more preferably from 60°C to 90°C.
  • the temperature of the annealing is sufficiently less than the softening point of the plastic substrate. For instance a temperature of less than 90°C is preferred to annealing a polycarbonate resin substrate.
  • the annealing may be carried out immediately subsequent to finishing the sputtering at a higher temperature than that used during the deposition of the film
  • the treated substrate is usually taken out of the sputtering vacuum system and cooled to room temperature before being subjected to the annealing.
  • the fluorine content in the deposited film is decreased by the annealing, in order to obtain the above-mentioned stable micro-structure after the annealing, since fluorine atoms effectively terminate the free bond of Te, the fluorine content in the film is generally from 0.l to 30, preferably from 1 to 20, atomic% after the annealing. There is a tendency for the crystal grain diameter to be larger than 100 nm (l000 ⁇ ) after the annealing when the fluorine content is below 0.l atomic%. Moreover, when the fluorine content is more than 30 atomic%, the pits have serious irregularities; accordingly such a high content is not preferred. When the fluorine content is more than 20 atomic%, there is a tendency for the crystallization temperature to be raised.
  • the micro-structure in the above-mentioned recording layer is sufficiently stabilized by annealing at a temperature of from not less than 60°C to less than l00°C, particularly at a temperature of not more than 90°C.
  • annealing at a temperature of from not less than 60°C to less than l00°C, particularly at a temperature of not more than 90°C.
  • the recording layer has been deposited directly on the substrate as described above, it is also possible to provide an underlayer between the substrate and the recording layer, for example to improve the recording sensitivity and the shape of pits. Furthermore it is possible to provide a protective layer on the recording medium to protect the recording medium. It is particularly effective to use an underlayer made of a fluorocarbon polymer. Various types of fluorocarbon polymer can be used depending on the the performance required of the optical recording medium obtained.
  • a dry-process in a vacuum is favorable for producing the underlayer from the viewpoint of uniformity of the layer, decrease of pin-holes and the constitution of in-line process with the recording layer.
  • a plasma polymerized film of a fluorocarbon, a sputtered film of a polyfluorocarbon and a vacuum evaporated film of a polyfluorocarbon can, for example, be used.
  • the fluorocarbon are a perfluoroalkane such as CF4 or C2F6 and a perfluoroalkene such as CF3CFCF2, perfluorohexane and perfluorobenzene.
  • Any fluorocarbon may be used even if it is a gas or liquid at normal temperatures, provided that the fluorocarbon has an adequately high vapour pressure, glow discharge can be sustained in a vacuum chamber after filling the chamber with the fluorocarbon vapour at a pressure of the order of higher than 0.13 Pa (10 ⁇ 3 Torr) and the fluorocarbon has a high degree of fluorine substitution.
  • the plasma polymerized fluorocarbon film can be formed by using the above-mentioned fluorocarbon as the monomer and using a capacitively coupled electric discharge or inductively coupled electric discharge.
  • the films may be deposited by sputtering of, for example, polytetrafluoroethylene, a copolymer of tetrafluoroethylene and hexafluoropropylene or a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene, in a gasous phase such as argon gas or a gaseous mixture of an inert gas and the above-mentioned monomer.
  • a gasous phase such as argon gas or a gaseous mixture of an inert gas and the above-mentioned monomer.
  • the thickness of the fluorocarbon polymer underlayer is generally from 10 to 100 nm (100 to 1000 ⁇ ).
  • the fluorocarbon polymer underlayer influences, for example, the shape of the pits, the presence or absence of remnants in the pits and the recording sensitivity of the recording medium, depending on the condition of the interface between the underlayer and the recording layer. Accordingly, exact evaluation of the composition and the structure of the underlayer surface of the fluorocarbon polymer, and the control thereof during manufacturing, are important.
  • An example of an evaluating method is the ESCA method (electron spectroscopy for chemical analysis).
  • the kinds of elements, their composition and the state of chemical bonding in the vicinity of the surface of the specimen can be analyzed from the energy spectrum of photoelectrons emitted by the atoms in the compounds of the specimen by irradiation with soft X-rays.
  • the spectrum of the fluorine lS orbital(F lS ) and the spectrum of the carbon lS orbital(C lS ) on the surface of a fluorocarbon polymer thin film before forming the recording layer thereon were determined using an ESCA spectrometer "XSAM-800" made by the SPECTROS Company.
  • the F lS spectrum consists of a single peak having a center in the vicinity of 688 eV binding energy
  • the C lS spectrum consists of several peaks having centers in the region of from 285 to 294 eV binding energy.
  • the -CF3 and >CF2 peaks can be discriminated particularly clearly from the other binding states, and may be identified by comparison with reference chemical shifts according to the method disclosed in various literature (e.g. D.T. Clark and D. Shuttleworth, J. Poly. Sci., l8(80) page 27; and K. Nakajima, A.T. Bell and M. Shen, J. Appl. Poly. Sci., 23(79) page 2627).
  • the ratio of each integral peak area intensity to the whole integral intensity of C lS is calculated to obtain the values "-CF3/C" and ">CF2/C".
  • "-CF3/C” is the ratio of the number of carbon atoms forming -CF3 groups to the total number of carbon atoms
  • ">CF2/C” is the ratio of the number of carbon atoms forming the >CF2 groups to the total number of carbon atoms.
  • the ratio of the number of fluorine atoms to the number of carbon atoms can be calculated from the peak area ratio of C lS to F lS .
  • compositions and the structure of the fluorocarbon polymer underlayer obtained by the above-mentioned method and the specific properties of the optical recording medium, and furthermore the method of controlling the composition and the structure thereof are explained as follows. It is easy to select the most suitable composition and structure of the fluorocarbon polymer underlayer along with each type of recording layer containing Te, Se and F.
  • composition of the fluorocarbon polymer underlayer and the properties as an optical recording medium are primarily due to the ratio (F/C) of the number of fluorine atoms to the number of carbon atoms on the surface of the underlayer which contacts the recording layer.
  • the F/C ratio is less than 0.9, hardly any improvement of the sensitivity as compared to the case where the recording layer is deposited directly on the polycarbonate substrate is observed.
  • the power of the laser beam necessary for recording decreases monotonously; thus the recording sensitivity is improved.
  • the improvement of the recording sensitivity is saturated for a F/C ratio of not less than l.4.
  • the F/C ratio is not less than l.4, there are no remnants in the pits and uniform pits having smooth and well-defined rims are formed without being dependent on the process for producing the underlayer and on the detailed morphology of the underlayer surface. A high C/N ratio can be attained. Accordingly to obtain an optical recording medium having particularly high sensitivity and C/N ratio, the F/C ratio should be not less than l.4.
  • the F/C ratio is from not less than 0.9 to less than l.4
  • remnants may remain in the pits and the shapes of the rim can be irregular under certain conditions for preparing the fluorocarbon polymer layer.
  • a high C/N ratio cannot be obtained when a F/C ratio of not less than l.4 cannot be obtained.
  • the C/N ratio in the case of an F/C ratio of from not less than 0.9 to less than l.4 is superior to that in the case when no underlayer is used.
  • the F/C ratio is preferably from not less than 0.4 to less than l.4.
  • An improvement of the C/N ratio can be obtained to some degree by using the above-mentioned conditions when the F/C ratio is not less than l.4 and not more than l.8.
  • the ratio F/C and the amount of >CF2 and -CF3 groups control the properties of the interface of the fluorocarbon polymer underlayer which contacts the recording layer, it is enough that only the surface region of the fluorocarbon polymer underlayer which contacts the recording layer has the above-mentioned composition. It is not necessary for the whole fluorocarbon polymer underlayer to have the above-mentioned composition.
  • the flexibility of the thin layer of fluorocarbon polymer can be optimized by only changing the raw materials thereof, such as the gaseous monomer or the sputtering target, or by controlling the discharge conditions even when using the same apparatus for fabricating the layer.
  • the capacitively coupled plasma polymerization can be actualized by only exchanging the target of the sputtering apparatus taking the parallel electrode structure with a material which is not subjected to sputtering such as stainless steel.
  • the plasma polymerization of a fluorocarbon monomer and the sputtering of the polyfluorocarbon can be carried out.
  • the above-mentioned method has a merit of having a large for selecting the process for production and the raw material. Furthermore, it is also easy to construct an in-line process including the process for preparing the recording layer by the reactive sputtering method.
  • the method for controlling the composition and structure of the thin fluorocarbon underlayer is now explained in detail:
  • the sputtering of the polyfluorocarbon e.g. a tetrafluoroethylene polymer, a copolymer of tetrafluoroethylene and hexafluoropropylene or a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene
  • the polyfluorocarbon e.g. a tetrafluoroethylene polymer, a copolymer of tetrafluoroethylene and hexafluoropropylene or a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene
  • the plasma polymerization of the fluorocarbon is carried out by introducing a fluorocarbon monomer under a pressure of from 0.67 to 1.3 Pa (5 ⁇ l0 ⁇ 3 to l ⁇ l0 ⁇ 2 Torr) also between the parallel electrodes and applying an electric field having a radio frequency thereon.
  • the vacuum evaporation may also be carried out by an electric resistance heating method.
  • the F/C ratio in the surface layer of the fluorocarbon polymer obtained by using a capacitively coupled plasma polymerization apparatus depends on the monomeric gas, the form of the apparatus, the conditions of electric discharge and, particularly, on the discharge power and the pressure of the gaseous monomer. An F/C ratio of from 0.2 to l.5 is easily achievable. In the surface of the fluorocarbon polymer layer obtained by sputtering, an F/C ratio of from l.l to l.8 is easily obtainable.
  • radicals such as -CF3 and >CF2 are generated as large amount as possible and made to impinge onto the glowing surface of the films.
  • the growing surface of the thin layer of fluorocarbon polymer, which has been adhered to the substrate is, as far as possible, not exposed to high energy particles (electrons and ions) in the plasma.
  • the F/C ratio of the target material is raised, the distance between the electrodes is increased and the power of the electrical discharge is raised to increase the deposition rate of the fluorocarbon polymer layer.
  • the F/C ratio can be further raised also by mixing a fluorocarbon monomer such as CF4 or C2F6 with the inert gas, such as argon, which is used in the sputtering. Furthermore, the F/C ratio can be raised by raising the F/C ratio of the evaporated polyfluorocarbon in the vacuum evaporation method.
  • a fluorocarbon monomer such as CF4 or C2F6
  • the inert gas such as argon
  • the substrate is established avoiding the internal part of the coil, where the plasma density is high.
  • the parallel electrodes are separated and the substrate is established on one of the electrodes, preferably on the electrode on the earth side.
  • the amount of >CF2 and -CF3 groups can be increased by using a lower electric discharge power, a higher gas pressure and a higher gas flow rate.
  • the ratio of the number of fluorine atoms to the number of carbon atoms in the fluorocarbon polymer underlayer which contacts the recording layer is from 0.9 to l.8. Furthermore not less than l8 atomic% of the total number of carbon atoms preferably present in the -CF3 groups and from not less than l8 atomic% to less than 40 atomic% of the total number of carbon atoms are preferably present in the >CF2 groups. It is necessary to control the fine structure shown by ESCA spectrum.
  • the structures of the plasma fluorocarbon polymerized layer and the fluorocarbon polymer sputtered layer reflect those of the gaseous monomer and the target material to a certain extent.
  • the -CF3 groups are contained in a large amount in the gaseous monomer or when the radicals and ions generated in the plasma are rich in CF3 groups, the -CF3 groups are apt to be taken into the polymerized layer. For instance, when using hexafluoropropylene as the monomer, it is possible to increase the amount of -CF3 groups in the polymerized layer to a greater extent than when using tetrafluoroethylene as the monomer.
  • the content of -CF3 group in the polymerized layer can again be raised. Still further, there is a tendency that a large amount of >CF2 groups are contained in a deposited layer made from monomer gas containing an unsaturated bond.
  • the layer deposited by sputtering polytetrafluoroethylene also reflects the structure of the target and contains >CF2 groups in a large amount.
  • the amount of -CF3 groups can be raised also by carrying out the reactive sputtering with a gaseous mixture obtained by mixing hexafluoropropylene or carbon tetrafluoride with argon gas.
  • a plasma polymerized layer of hexafluoropropylene which fulfills the requisites of the present invention has been obtained under the conditions of a pressure of 0.67 to 1.3 Pa (5 ⁇ l0 ⁇ 3 to l ⁇ l0 ⁇ 2 Torr), a gas flow rate of 300 to 500 cc/min (determined by a capillary-type flow meter set up for argon gas) and an electric discharge power of from l00 to 200 W.
  • the electric discharge conditions depend on the shape and performance of the apparatus used (size and shape of the vacuum chamber, vent property, method by which the reactive gas is introduced, and shape, size and structure of the electrodes). Accordingly, in the above-mentioned description and the following Examples, concrete values of, for example, the electric discharge gas pressure, flow rate and electric discharge are optimalized according to the individual apparatus. The present invention is not limited by the above-mentioned concrete values. Furthermore, when using an apparatus having the same shape, size, structure and performance, it is easy to have reproducibility.
  • a chlorofluorocarbon polymer may be used as the underlayer.
  • a thin layer of chlorofluorocarbon is obtainable by sputtering of polychlorotrifluoroethylene, reactive sputtering of polytetrafluoroethylene in a gaseous mixture of argon gas and a chlorofluorocarbon gas such as FREON ll3 (Trade Mark) (CCl2F - CClF2) or a chlorofluorocarbon plasma treatment on the surface of the deposited layer by sputtering of polytetrafluoroethylene.
  • the thin layer of chlorofluorocarbon is also obtainable by plasma polymerization using the chlorofluorocarbon gas as the monomer.
  • the thickness of the above-mentioned layer is generally from 2 to 100 nm (20 to l000 ⁇ ).
  • the composition of the surface of the underlayer which contacts the recording layer is made to be the above-mentioned composition. It is not necessary to make the composition of the whole underlayer to be the above-mentioned composition.
  • the adhesion can be improved, the shortest pit length is shortened and on the other hand, high sensitivity and an improvement in the shape of the pits can be achieved.
  • the recording layer is an alloy containing Te and Se
  • the surface tension of the surface of the fluorocarbon polymer layer becomes larger, and moreover, due to the crosslinking of the carbon atoms, the density and the molecular weight of the crosslinked layer on the surface of the fluorocarbon polymer layer are raised.
  • the thickness and the degree of crosslinking of the surface layer can be controlled by the conditions of plasma discharge, particularly by the power of the discharge, the duration of exposure to the plasma and the distance between the substrate and the electrode. As a result it is possible to control within wide limits the adhesion of the recording layer to the underlayer and to optimize the properties of each kind of recording layer.
  • a sputtered layer of polytetrafluoroethylene (PTFE) was prepared, and the layer was subjected to the plasma treatment by argon plasma under a pressure of 0,67 Pa (5 ⁇ l0 ⁇ 3 Torr) at a discharge power of l00 W. Thereafter the contact angle of the layer and the F/C ratio within l0 nm from the surface of the layer were measured by the ESCA method as previously described.
  • PTFE polytetrafluoroethylene
  • Fig. 2 shows one example of an apparatus for producing an optical recording medium according to the present invention by reactive sputtering.
  • (5) is a vacuum chamber
  • (6) are cathode and anode electrodes
  • (7) is an alloy target containing Te and Se
  • (8) is a substrate
  • (9) is a gas inlet
  • (l0) is a shutter
  • (ll) is an exhaust gas outlet.
  • the vacuum chamber (5) was evacuated to a back pressure of about 13 mPa (l0 ⁇ 6 Torr) and then argon gas was introduced into the chamber (5) from the gas inlet (9) to raise the inner pressure of the chamber (5) to 0.67 Pa (5 ⁇ l0 ⁇ 3 Torr).
  • a radio frequency voltage at l3.56 MHz was continuously applied between the electrodes (6) to cause a glow discharge for about l0 minutes to clean the surface of the target (7).
  • the inner space of the chamber (5) was evacuated again to 13 mPa (l0 ⁇ 6 Torr) and a gaseous mixture of 90% by volume of argon and l0% by volume of gaseous SeF6 was introduced into the chamber (5) from the gas inlet (9) to make the total pressure 0.67 Pa (5 ⁇ l0 ⁇ 3 Torr).
  • a radio frequency voltage of 50 W power at l3.56 MHz between the anode (6) on the side of the substrate and the cathode (6) on the side of the target (7) a glow discharge was created to carry out the sputtering.
  • an alloy of 88 atomic % of Te and l2 atomic % of Se was used, and a 40 nm thick sputtered layer was deposited on the substrate.
  • the content of Se in the deposited layer was l5 atomic %, and the content of fluorine atoms therein was 20 atomic %.
  • Recording and reading-out were carried out on the thus produced optical recording medium by a semiconductor laser diode of wavelength 830 nm (pulse width of 500 ns). A sensitivity of 4mW and a C/N ratio of 52 dB were obtained.
  • argon gas was introduced to a pressure of 1.3 Pa (l ⁇ l0 ⁇ 2 Torr) and using an electric glow discharge at l00 W and l3.56 MHz, a sputtered layer (F/C ratio of l.6) of about 15 nm (l50 ⁇ ) was deposited on a substrate of polycarbonate resin.
  • the electrode on the side of the substrate was moved right over the alloy target made of 88% Te and l2% Se, and after carrying out pre-sputtering, SeF6 gas was introduced into the chamber in a volume ratio of l0% to make the total pressure in the chamber 0.67 Pa (5 ⁇ l0 ⁇ 3 Torr). Thereafter, by applying a radio frequency voltage of 50 W power at l3.56 MHz between the electrode on the side of the substrate and the electrode on the side of the target, a glow discharge was caused to carry out the sputtering. A 40 nm thick sputtering layer was deposited on the substrate. The content of Se in the deposited layer was l5 atomic %, and the content of fluorine atoms therein was 20 atomic %.
  • Fig. l shows a longitudinal crosssectional view of the thus obtained optical recording medium.
  • (l) is a substrate
  • (2) is an underlayer
  • (3) is a recording layer
  • (4) is a channel for a track-servo.
  • the target an alloy of 85 atomic % Te and l5 atomic % Se was used, and a 40 nm (400 ⁇ ) thick Te-Se deposited layer was formed on the substrate.
  • the C/N ratio was 45 dB.
  • the recording sensitivity was 4.5 mW. There were local irregularities of recording sensitivity.
  • the vacuum chamber was evacuated to 1.3 x 10 ⁇ 4 Pa (l0 ⁇ 6 Torr) and then SeF6 gas and argon gas were introduced thereinto at a flow ratio shown in Table l.
  • SeF6 gas and argon gas were introduced thereinto at a flow ratio shown in Table l.
  • the discharge power and the pressure within the vacuum chamber were as shown in Table l.
  • Glass substrates of 12 mm thickness were used.
  • the thickness of each deposited layer was from 30 to 40 nm (300 to 400 ⁇ ).
  • the fluorine content (shown by atomic %) of the layer after annealing is shown in Table l.
  • the dependency of the transmission of the recording layer on the temperature was measured.
  • Fig. 3. shows details of the specimen of Example 4 in Table l in the case of raising the temperature at l3°C/minute.
  • the recording medium of Examples 4 and 5 and Comparative Example 2 and 3 was formed on a disk-shaped polycarbonate resin substrate with a hexafluoropropylene polymer underlayer was formed on the substrate.
  • the changes in the properties of the disk were examined before and after annealing, which was carried out in air at 80°C for one hour.
  • the reflectivity of the recording medium became about l.l times the initial value and stabilized at that level.
  • Example 4 a stabilized and uniform micro-structure was formed by annealing, which did not show any unfavorable effects such as noise in the readout signal. There was no local irregularity of the sensitivity and uniform pits were formed. As a result, an improvement of from 2 to 3 dB in C/N ratio was achieved.
  • the grain size of the crystals of the recording medium according to the present invention is small, and it is possible to control the crystallization temperature, particularly to not less than 90°C.
  • optical properties were quite stable in an accelerated test at 65°C and 80% RH. Also, on examining the change in quality of the recording medium due to repeated irradiation on the same track by the readout light, degradation in quality of the medium before annealing began at a power of the readout laser beam of l.3 mW and accurate readout was impossible. However the medium was quite stable after annealing.
  • Example 6 annealing at a temperature of not less than 90°C was necessary to obtain the same effect as the above.
  • Such a medium was not suitable for using with a disk shaped substrate of a polycarbonate resin with a hexafluoropropylene polymer underlayer.
  • Each of several fluorocarbon polymer underlayers as shown in Table 2 was provided on a substrate (l30 mm diameter and l.2 mm thickness) of polycarbonate resin by sputtering or plasma polymerization.
  • the sputtering of the fluorocarbon polymer (tetrafluoroethylene resin, copolymer of tetrafluoroethylene and hexafluoropropylene or copolymer of tetrafluoroethylene and perfluoroalkoxyethylene) was carried out by introducing argon gas under a pressure of from 0.67 to 1.3 Pa (5 ⁇ l0 ⁇ 3 to l ⁇ l0 ⁇ 2 Torr) between parallel electrodes and applying a radio frequency voltage of from 50 to 200 W power at l3.56 MHz.
  • the plasma polymerization of the fluorocarbon (tetrafluoroethylene or hexafluoropropylene) was carried out also by introducing the gaseous monomer under a pressure of from 0.67 to 1.3 Pa (5 ⁇ l0 ⁇ 3 to l ⁇ l0 ⁇ 2 Torr) between the parallel electrodes and applying a radio frequency voltage of from l00 to 600 W power at l3.56 MHz.
  • the reactive sputtering was carried out on the underlayer while using an alloy target consisting of 88% Te and l2% Se and introducing SeF6 gas and argon gas in the same manner as in Example l.
  • a 40 nm (400 ⁇ ) thick recording layer was formed.
  • the composition of the thus obtained layers is the same as that in Example l.
  • the recording and reading-out was carried out by a semiconductor laser beam using the above-mentioned optical recording medium on a 130 mm diameter disk-shaped substrate of polycarbonate resin.
  • the power of the laser beam necessary for writing was taken as the recording sensitivity.
  • the shapes of the formed pits and the presence or absence of remnants in the pits were observed by scanning electron microscopy (SEM).
  • the rim of the pit was well-defined without any irregularity and the C/N ratio of the optical recording medium was improved by a few dB as compared to the case where remnants were present.
  • Te88Se12 As the recording layer on the thus formed underlayer in a gaseous mixture of argon and SeF6, a medium of TeSe-SeF6 series (consisting of l5 atomic% Se, 20 atomic % F and the balance Te, and having a thickness of 40 nm (400 ⁇ )) was prepared. Evaluation of the writing and reading-out properties of the medium was carried out under the following conditions:
  • the disk-shaped substrate was rotated at l800 rpm, and recording and reading-out were carried out on the tracks at a distance of about 30 mm from the rotating axis by a semiconductor laser diode of a wavelength of 830 nm.
  • the recording was carried out by a pulse light of l.0 MHz and duty of 50 %.
  • the dependency of the C/N ratio (carrier to noise ratio) to the recording power is shown in Fig. 4 (a).
  • the C/N ratio was larger than 55 dB and showed a stable specific property within a broad range of the recording power. On carrying out SEM observation, remnants could scarcely be found in the pits.
  • FIG. 4 shows the dependency of the C/N ratio on the recording power in the case of forming the same recording layer as in Example 2 on the polytetrafluororethylene underlayer by sputtering, wherein the ratio of the number of fluorine atoms to the number of carbon atoms was l.5 [in the case of (b)] and l.25 [in the case of (c)]. Also in Fig. 4 (d) shows the case where the recording layer was directly formed on the polycarbonate substrate without using an underlayer.
  • FIG. 4 shows the case wherein a reactive sputtering of polychlorotrifluoroethylene was carried out in a gaseous mixture of argon gas and CCl2F-CClF2 to form a layer in which the ratio of the number of fluorine atoms to the number of carbon atoms was 0.85 and which contained l9 atomic % of chlorine, as the underlayer.
  • Sputtering of polytetrafluoroethylene was carried out under a pressure of argon gas of 1.3 Pa (l ⁇ l0 ⁇ 2 Torr) and at a discharge power of 200 W to form a thin layer having a thickness of about 20 nm (200 ⁇ ) on a disk-shaped polycarbonate resin substrate. Thereafter, the thus prepared material was subjected to plasma treatment under a pressure of argon gas of 0.7 Pa (5 ⁇ l0 ⁇ 3 Torr) at a discharge power of 50W for 30 seconds.
  • Fig. 5 shows the dependency of the C/N ratio on the recording power.
  • a1 shows the case for the underlayer which has not been treated in the plasma
  • b1 shows the case of the plasma treated underlayer
  • c1 shows the case without having an underlayer.
  • the sensitivity of the medium b1 was better than the sensitivity of the medium c1
  • the C/N ratio of the medium b1 was larger than C/N ratio of the medium a1 by from 2 to 3 dB
  • the dependency of the C/N ratio of the medium b1 on the recording power was smaller than that of the medium a1. It was found as a result of observation by SEM that the above-mentioned facts were due to the relatively slight increase of the pit size in the medium b1 in contrast to the rapid increase of the pit size in the medium a1 with increase of recording power.
  • the amount of remnants in the pits was smaller in b1 than in c1, and a uniform rim was formed in b1.
  • the plasma treating conditions for obtaining the optimized property of b1 can be decided by the ESCA method.
  • a polymethyl methacrylate resin (PMMA) or polycarbonate resin (PC) substrate which had been preliminarily washed was set in a vacuum room, and after evacuating to about 1.3 x 10 ⁇ 4 Pa (l ⁇ l0 ⁇ 6 Torr), 20 cm3/min of argon (determined by a capillary-type flow meter) and 5 cm3/min of SeF6 (determined by a capillary-type flow meter set up for argon) were introduced into the room to raise the pressure thereof to about 0.67 Pa (5 ⁇ l0 ⁇ 3 Torr).
  • Te was used as a target material.
  • Reactive sputtering using a high frequency power of 50 W for l5 seconds between electrodes at a distance of 80 mm was carried out to form a deposited layer of about 25 nm (250 ⁇ ) thickness.
  • the pits were formed by a pulse width of 200 nsec, and on the layer deposited on the PC substrate, the pits were formed by a pulse width of 250 nsec.
  • the light reflectivity (in the extent of 30%) at 830 nm did not show any change before and after the acceleration.

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Claims (18)

  1. Optisches Aufzeichnungsmedium, auf dem eine Information durch Strahlung mit einem Laserstrahl aufgezeichnet werden kann, wobei das Medium umfasst:
    (a) ein Substrat und
    (b) eine Aufzeichnungsschicht, die, basierend auf der Zusammensetzung der Schicht, von 35 bis 94,9 Atom-% Te, von 5 bis 25 Atom-% Se und von 0,1 bis 40 Atom-% F enthält.
  2. Optisches Aufzeichnungsmedium nach Anspruch 1, dadurch gekennzeichnet, dass die Aufzeichnungsschicht durch reaktives Bedampfen erzeugt ist, wobei sich das Se von Selenfluorid und einem Bedampfungstarget ableitet, das eine Te-Se-Legierung enthält.
  3. Optisches Aufzeichnungsmedium nach Anspruch 1, dadurch gekennzeichnet, dass die Aufzeichnungsschicht durch reaktives Bedampfen unter Verwendung von Selenfluorid und einem Target aus Te erzeugt ist.
  4. Optisches Aufzeichnungsmedium nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass eine Unterschicht, die ein Fluorkohlenstoffpolymer enthält, zwischen dem Substrat (a) und der Aufzeichnungsschicht (b) angeordnet ist, wobei das Atomverhältnis von Fluor zu Kohlenstoff an der Oberfläche der Unterschicht, die die Aufzeichnungsschicht kontaktiert, 0,9 bis 1,8:1 beträgt, gemessen entsprechend dem ESCA-Verfahren.
  5. Optisches Aufzeichnungsmedium nach Anspruch 4, dadurch gekennzeichnet, dass die Unterschicht ein bedampfter Film aus Polytetrafluorethylen oder ein plasmapolymerisierter Film aus Hexafluoropropylen oder Tetrafluoroethylen ist.
  6. Optisches Aufzeichnungsmedium nach Anspruch 4 oder 5, dadurch gekennzeichnet, dass nicht weniger als 18 % der Kohlenstoffatome an der Oberfläche der Unterschicht, die die Aufzeichnungsschicht kontaktiert, in Form von -CF₃-Gruppen vorhanden sind und dass von 18 % bis weniger als 40 % der Kohlenstoffatome an der Oberfläche in Form von >CF₂-Gruppen vorhanden sind.
  7. Optisches Aufzeichnungsmedium nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass eine Unterschicht, die ein Chloro-fluorokohlenstoffpolymer enthält, zwischen dem Substrat (a) und der Aufzeichnungsschicht (b) angeordnet ist, wobei das Atomverhältnis von Fluor zu Kohlenstoff an der Oberfläche der Unterschicht, die die Aufzeichnungsschicht kontaktiert, 0,9 bis 1,4:1 ausmacht und dass die Oberfläche von 5 bis 15 Atom-% Chlor enthält.
  8. Verfahren zur Herstellung eines optischen Aufzeichnungsmediums, gekennzeichnet durch Durchführen einer reaktiven Bedampfung in einer gasförmigen Mischung aus einem Selenfluoridgas und einem Argongas, während eine Legierung, die Te und Se enthält, als ein Targetmaterial verwendet wird, um so eine Aufzeichnungsschicht auf einem Substrat zu bilden, die, bezogen auf die Zusammensetzung der Schicht, von 35 bis 94,9 Atom-% Te, von 5 bis 25 Atom-% Se und von 0,1 bis 40 Atom-% F enthält.
  9. Verfahren nach Anspruch 8, dadurch gekennzeichnet, dass eine Te-Se-Legierung, die von 1 bis 30 Atom-% Se enthält, als das Targetmaterial verwendet wird.
  10. Verfahren zur Herstellung eines optischen Aufzeichnungsmediums, gekennzeichnet durch Durchführen einer reaktiven Bedampfung in einer gasförmigen Mischung aus einem Selenfluoridgas und Argongas, während ein Target aus Te verwendet wird, um so eine Aufzeichnungsschicht auf einem Substrat zu bilden, die, bezogen auf die Zusammensetzung der Schicht, von 35 bis 94,9 Atom-% Te, von 5 bis 25 Atom-% Se und von 0,1 bis 40 Atom-% F enthält.
  11. Verfahren nach einem der Ansprüche 8 bis 10, dadurch gekennzeichnet, dass der Anteil an Selenfluoridgas in der gasförmigen Mischung von 0,1 bis 50 Vol.% ausmacht.
  12. Verfahren nach einem der Ansprüche 8 bis 11, dadurch gekennzeichnet, dass die Aufzeichnungsschicht eine niedergeschlagene Schicht enthält, die Te, Se und F umfasst, die bei einer Temperatur von 60 bis 130°C ausgeglüht sind.
  13. Verfahren nach Anspruch 12, dadurch gekennzeichnet, dass die ausgeglühte niedergeschlagene Schicht eine polykristalline Struktur von Kristallen mit einem Teilchendurchmesser von weniger als 1000 Angström aufweist.
  14. Verfahren nach Anspruch 12 oder 13, dadurch gekennzeichnet, dass das Ausglühen bei einer Temperatur von 60 bis 100°C durchgeführt wird.
  15. Verfahren nach einem der Ansprüche 12 bis 14, dadurch gekennzeichnet, dass der Fluorgehalt in der ausgeglühten niedergeschlagenen Schicht von 0,1 bis 30 Atom-% ausmacht.
  16. Verfahren nach einem der Ansprüche 8 bis 15, dadurch gekennzeichnet, dass eine Unterschicht, die ein Fluorkohlenstoffpolymer enthält, zwischen der Aufzeichnungsschicht, die Te, Se und F enthält, und dem Substrat angeordnet wird.
  17. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass die Unterschicht auf dem Substrat durch eine Plasmapolymerisation eines Fluorkohlenstoffes oder durch Bedampfen von einem Polyfluorkohlenstoff gebildet wird.
  18. Optisches Aufzeichnungsmedium, auf dem eine Information aufgezeichnet ist, wobei das Medium ein Medium nach einem der Ansprüche 1 bis 7 ist oder durch ein Verfahren nach einem der Ansprüche 8 bis 17 hergestellt ist.
EP87301046A 1986-04-24 1987-02-05 Optisches Aufzeichnungsmedium und Verfahren zu dessen Herstellung Expired - Lifetime EP0242942B1 (de)

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JP61095264A JPS62252543A (ja) 1986-04-24 1986-04-24 光学的記録用媒体
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JP142167/86 1986-06-18
JP61142167A JPS62298944A (ja) 1986-06-18 1986-06-18 光学的記録用媒体
JP61220833A JPS6374139A (ja) 1986-09-18 1986-09-18 光学的記録用媒体
JP220833/86 1986-09-18
JP302607/86 1986-12-18
JP61302607A JPS63155443A (ja) 1986-12-18 1986-12-18 光学的記録用媒体
JP306073/86 1986-12-22
JP61306073A JPS63160027A (ja) 1986-12-22 1986-12-22 光学的記録用媒体
JP307120/86 1986-12-23
JP61307120A JPS63160031A (ja) 1986-12-23 1986-12-23 光学的記録用媒体
JP2966/87 1987-01-09
JP62002966A JPS63171446A (ja) 1987-01-09 1987-01-09 光学的記録用媒体の製造方法
JP62013650A JPS63182188A (ja) 1987-01-23 1987-01-23 光学的記録用媒体
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US7659049B2 (en) 2002-03-05 2010-02-09 Mitsubishi Kagaku Media Co., Ltd. Phase-change recording material used for information recording medium and information recording medium employing it

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EP0405450A3 (en) * 1989-06-30 1991-08-21 Kabushiki Kaisha Toshiba Data recording medium and method of manufacturing the same

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DE2718157A1 (de) * 1977-04-23 1978-11-02 Licentia Gmbh Verfahren zum herstellen eines elektrophotographischen aufzeichnungsmaterials

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US7659049B2 (en) 2002-03-05 2010-02-09 Mitsubishi Kagaku Media Co., Ltd. Phase-change recording material used for information recording medium and information recording medium employing it

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